strainrelief

Strain relief, sometimes written as strain-relief, is a feature or component that prevents excessive mechanical stress from reaching a cable termination when a cable is pulled, twisted, or bent. By distributing load and reducing flexing at the termination, it helps prevent insulation wear, conductor fatigue, and connector loosening. Strain relief is typically placed at cable entry points into enclosures, power supplies, and devices, and may be built in or added as an external fitting.

Common forms include molded or overmolded relief sections in housings, external cable glands, grommets, clamps, ferrules, and flexible boots. In many products the strain-relief feature is integrated into the enclosure wall to create a gentle bend radius and a secure termination. For heavier cables, locking glands or metal clamps may be used to increase strength and protect against high-torque pulls.

Design considerations include material choice (nylon, polyurethane, elastomer, or metal) with suitable temperature and chemical resistance; bend radius and termination length; and environmental or regulatory requirements (IP, NEMA, UL/CE). The aim is to spread the pulling force and preserve termination integrity under vibration, thermal cycling, and assembly tolerances.

Applications span consumer electronics, automotive and industrial equipment, telecommunications, medical devices, and any product with cables entering an enclosure. Testing typically involves pull tests, dynamic flex tests, and aging to verify retention, bend stiffness, and insulation protection. While terms vary, strain relief is a design objective focused on mechanical load management rather than electrical function alone.